1. Technical Field
The present disclosure relates to electrosurgery. More particularly, the present disclosure relates to an automatic control system for an electrosurgical generator.
2. Background of Related Art
Surgeons have tried to deal with energy application by adjusting the basic power level of the electrosurgical generator and using a hand or foot switch to control the power applied over time. Unfortunately, that technique often leads to unintended power delivery or undesired duration of power delivery to the surgical site. Surgeons also experience difficulty in repeatably and/or consistently desiccating tissue to the desired levels due to the user's reaction time and/or machine response time when manual or foot activated switches are used for manual control. In addition, during endoscopic procedures, visual and tactile feedback is diminished.
A circuit for automatically controlling the output of an electrosurgical generator is disclosed in U.S. Pat. No. 6,210,403 to Klicek, currently owned, and assigned to Sherwood Services AG, the contents of which are hereby incorporated by reference in its entirety. U.S. Pat. No. 6,210,403 relates to an electrosurgical generator control, which is responsive to the tissue impedance between the active and return electrodes during desiccation.
A method for tone detection using the Goertzel algorithm is disclosed in an article entitled The Goertzel Algorithm by Kevin Banks (The Goertzel Algorithm by Kevin Banks, <http://www.embedded.com/showArticle.jhtml?articleID=9900772>, last visited on Jul. 24, 2003). The Banks' article relates to using a modified Goertzel algorithm for determining whether a tone of a specific frequency is present. The Goertzel algorithm calculates both the magnitude and the phase of signal at a specific frequency and is functionally equivalent to performing a Discrete Fourier Transform (DFT) at a single frequency, but is much less computationally demanding. The DFT is a method for calculating the magnitude and phase of a band of frequencies of interest. An N-point DFT is computationally demanding, but will calculate the real and imaginary frequency terms for all the frequencies up to half the sampling rate of the signal.
According to Banks, using a modified Goertzel algorithm is preferable in applications requiring tone detection such as DTMF, call progress decoding, and frequency response measurements. However, the modified Goertzel algorithm proposed by Banks does not provide the real and imaginary frequency components of the sampled waveform. As a result, the modified Goertzel algorithm is unsuited for determining the phase of the waveform.
It is an object of the present disclosure to provide an automatic control system that uses fewer computational steps.
Another object of the present disclosure is to provide an automatic control system that measures the power delivered to a patient.
Yet a further object of the present disclosure is to provide an automatic control system that is adaptable to both monopolar and bipolar electrosurgical generator configurations.
It is a further object of the present disclosure to provide an automatic control system that adjusts the power delivered to a patient by an electrosurgical generator.